any suggestions one exhaust for a 509 making 700 hp.

Do I need a long header or will a e-top work?

Sounds like some pretty good numbers. Anytime you go longer runners you will make more power however how much more with this application I don't know for sure. 15HP??? Just a guess. PM Brian41 and see what he says. He does a lot of back to back testing and is full of knowledge.

E-tops (dry) will support 700 HP on 509's...4.5 ID tails are best

thanks guys!!!!!

do a study on etops . i been reading a lot of promblems on them leaking . i run stainless marine headers 540cube 650hp . just make shore that what you want ??